Etiolation Study

Title

Author(s)

Question

What is the effect of darkness on the germination and growth of pinto beans?

Standards

Structure and Function in Living Systems

6. The anatomy and physiology of plants and animals illustrate the
complementary nature of structure and function. As a basis for
understanding this concept:

a. Students know plants and
animals have levels of organization for structure and function,
including cells, tissues, organs, organ systems, and the whole
organism.

b. Students know organ systems function
because of the contributions of individual organs, tissues, and cells.
The failure of any part can affect the entire system.

Investigation and Experimentation

7. Scientific progress is made by asking meaningful questions and
conducting careful investigations. As a basis for understanding this
concept and addressing the content in the other three strands, students
should develop their own questions and perform investigations. Students
will:

e. Communicate the steps and results from an investigation in written reports and oral presentations.

Experimental Design

Before the experiment, there should probably be a discussion or a lesson on germination and the requirements for plant growth. After the discussion, students need to write a hypothesis statement about the effect of darkness on germination and growth of beans. Then they should set up their experiment by creating two groups of plants. One batch of beans should be kept in darkness for the duration of their growth. The other set should be kept in light. Students need to observe and record the growth of the main shoot of the beans for both groups. Then they will compare the two groups to determine the validity of their hypothesis.

Independent variable

Presence of Light

Dependent variables

Rate of Growth

Series

N/A.

Constants

Level of Water.

Temperature.

Air content.

Materials

paper towels

newspaper

clear plastic cups or glass beakers

pinto beans

ruler

painter's tape

marker

digital camera

Procedures

Wet two paper towels then line the walls of a large beaker with the towels. They should stick to the glass.

Fill the core of the beaker with a crumpled sheet of newspaper. The newspaper will hold the wet towels in place.

Pour water into the bottom of the glass until it is about 2-3 cm. deep.

Now "plant" the beans between the glass wall of the beaker and the wet paper towels. Place them turned in different directions.

Use a glass-marking pen to number your seeds. (Or alternatively, cut painter's tape into tiny piece for numbering).

Record this information in lab journals.

Repeat #1-6 with a different set of beans.

Place one beaker in darkness (inside cabinet or closet will do) and the other near a light source (window or plant lamp).

Record qualitative observations and growth of the main shoot (in millimeters or centimeters) daily in lab journals.